The present disclosure, for example, relates to wireless communication systems, and more particularly to reporting of channel state information in a system employing variable length transmission time intervals.
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment's (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE). LTE is designed to improve spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards. LTE may use OFDMA on the downlink (DL), single-carrier frequency division multiple access (SC-FDMA) on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology.
In some instances, one or more parameters used for wireless communications may be determined, at least in part, by the channel conditions associated with a particular communications channel being used by a UE and base station for wireless communications. Channel state information may be estimated, in some instances, by a UE that receives a reference signal from a base station. This channel state information (CSI) may be periodically transmitted in a CSI report from the UE to the base station. In situations where the uplink and downlink transmission status of a system may be modified dynamically, reporting of CSI at set time intervals may result in conflicts between a scheduled CSI report transmission, which is to be transmitted in an uplink transmission from the UE to the base station, and a dynamically scheduled downlink transmission from the base station to the UE. Thus, flexible transmissions of CSI reports may enhance the efficiency of such systems.